This investigation will be concerned with the mechanism of acetal hydrolysis in the attempt to gain information regarding the chemical possibilities by which glycosidases might be acting. Differences in the non-enzymatic hydrolysis of acetals and the enzymatic hydrolysis of glycosides indicate that the enzymes are using mechanisms to which there are few analogies in organic chemistry. It will be the purpose of this investigation to demonstrate some of the mechanistic possibilities in non-enzymatic systems. It will also be the purpose of this investigation to elucidate more completely the mechanism of action of lysozyme.